The major objectives of this proposal are to determine the nature of proteins forming intracellular complexes with potentially toxic metals (lead and mercury), the role of these complexes in metal toxicity, and the effect of various chelating agents to remove the metals after formation of the protein-metal complexes. Lead, mercury, copper and bismuth are known to bind intracellularly with acidic nuclear proteins; but it is not known whether these proteins are synthesized in response to metals, similar to metallothionein induction. These studies will involve the formation of cytoplasmic and nuclear inclusion bodies in primary rat kidney cells in response to metal exposure and the effect of inhibitors of protein synthesis (cycloheximide and actinomycin-D). Since the alterations in heme synthetic pathway are very sensitive indicators of lead toxicity, the changes in gamma aminolevulinic acid synthetase and heme synthetase after exposure to lead will be studied in tissue culture using control cells and those containing inclusion bodies (pre-exposed to lead). These studies will be extended to rats fed with lead for a week and then treated with actinomycin-D to prevent the formation of inclusion bodies. The measurement of urinary excretion of lead and ALA in these rats will be a useful model to study the role of inclusion bodies on lead toxicity. If protein-metal complexing has any protective effects against lead toxicity, possible induction of these proteins will be studied by prior exposure to less toxic metals (copper). The effect of induction of metallothionein on the formation of inclusion bodies and chelation of lead with EDTA, BAL or DMSA in cells containing lead inclusions will be studied in cell culture. From these studies it is intended to identify the metabolic factors influencing the formation of lead inclusion bodies and the binding of mercury to acidic nuclear proteins. A better knowledge of protein-metal interactions in the metabolism and toxicity of metals at the cellular level is useful to modify the toxic effects of metals and probably in the treatment of metal poisoning.